1. Field of the Invention
Example embodiments of the present invention relate to probe sensing pads and methods of detecting contact sites for probe needles using the same. More particularly, example embodiments of the present invention relate to probe sensing pads for detecting whether probe needles making contact with desired contact sites or not, and methods of detecting and correcting positions of probe needles relative to the probe sensing pads.
2. Description of the Related Art
Modern semiconductor devices (or chips) are characterized by increasingly dense circuitry. After forming such chips on a substrate, an electric die sorting (EDS) process is carried out on the chips to electrically inspect for accurate construction of chip structures. Incorrectly formed structures are repaired, if possible, or removed from use.
During the EDS process, probe needles of a probe card are aligned with respective pads on the semiconductor device. Electrical signals are then generated by the chips and transmitted through the pads to respective probe needles. If all signals are received accurately, then the chip has been properly structured, otherwise a problem is detected.
More complex chips require greatly increased pads. Accordingly, to reduce a testing, a plurality of pads of the chips may be simultaneously contacted with probe needles of a probe card during one EDS process. The chance of misalignment increases as the number of simultaneous tests increases. Furthermore, the needles may be required to make contact with the pads several times if multiple tests are required. Therefore, the possibility that the probe needles make precise contact with desired normal contact sites of the pads may be considerably lowered.
When the probe needles of the probe card make contact with edge portions of the pads instead of the desired normal contact sites of the pads, the pads may be damaged by the probe needles and the EDS process may not properly carrier out. Further, abnormal contacts between the probe needles and the edge portions of the pads may not be easily detected by electrical open/short test steps so that probe failures may be continuously generated in successive EDS processes for other chips formed on substrates. When probe failures occur in the EDS processes, normal chips may be damaged. This damage lowers the yield of semiconductor manufacturing processes. Furthermore, misalignment of the probe needles has been traditionally difficult to detect accurately, further decreasing the efficiency of probing and EDS operations.
Accordingly, the need remains for embodiments that more easily and rapidly identifying, and later correcting, probe failures between probe sensing pads and respective probe needles.